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Reset the proxy when the destructor of the underlying pointer throws #82

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Merged
mingxwa merged 2 commits into from
Sep 9, 2026
Merged

Reset the proxy when the destructor of the underlying pointer throws #82

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249c6fd
Reset the proxy when the destructor of the underlying pointer throws
mingxwa Sep 8, 2026
7ec78d0
Fix MSVC failure
mingxwa Sep 9, 2026
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17 changes: 6 additions & 11 deletions include/proxy/v4/detail/core.h
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Original file line number Diff line number Diff line change
Expand Up @@ -385,9 +385,7 @@ R invoke_dispatch(Args&&... args) {
template <class P>
struct destroying_guard {
explicit destroying_guard(P* p) noexcept : p_(p) {}
~destroying_guard() noexcept(std::is_nothrow_destructible_v<P>) {
std::destroy_at(p_);
}
~destroying_guard() noexcept(std::is_nothrow_destructible_v<P>) { p_->~P(); }

private:
P* p_;
Expand Down Expand Up @@ -617,10 +615,7 @@ struct copy_dispatch {
}
};
struct destroy_dispatch {
template <class T>
PRO4D_STATIC_CALL(void, T& self) noexcept(std::is_nothrow_destructible_v<T>) {
std::destroy_at(&self);
}
PRO4D_STATIC_CALL(void, auto&&) noexcept {}
};
template <class D, class ONE, class OE, constraint_level C>
struct lifetime_meta_traits : std::type_identity<void> {};
Expand Down Expand Up @@ -925,8 +920,8 @@ struct facade_traits : specialization_t<facade_conv_traits_impl,
void(void*) const, F::copyability>,
lifetime_meta_t<relocate_dispatch, void(void*) && noexcept,
void(void*) &&, F::relocatability>,
lifetime_meta_t<destroy_dispatch, void() noexcept, void(),
F::destructibility>,
lifetime_meta_t<destroy_dispatch, void() && noexcept,
void() &&, F::destructibility>,
typename facade_traits::conv_meta,
typename facade_traits::refl_meta>>;
using indirect_accessor = composite_t<
Expand Down Expand Up @@ -1331,8 +1326,8 @@ class proxy : public detail::facade_traits<F>::direct_accessor,
if constexpr (F::destructibility != constraint_level::trivial) {
if (meta_.has_value()) {
invoke<detail::destroy_dispatch,
void() noexcept(F::destructibility ==
constraint_level::nothrow)>(*this);
void() && noexcept(F::destructibility ==
constraint_level::nothrow)>(std::move(*this));
}
}
}
Expand Down
4 changes: 2 additions & 2 deletions include/proxy/v4/detail/proxy_creation.h
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Expand Up @@ -78,7 +78,7 @@ template <class Alloc, class T>
void deallocate(const Alloc& alloc, T* ptr) {
auto al =
typename std::allocator_traits<Alloc>::template rebind_alloc<T>(alloc);
std::destroy_at(ptr);
ptr->~T();
al.deallocate(ptr, 1);
}
template <class Alloc>
Expand Down Expand Up @@ -223,7 +223,7 @@ class strong_compact_ptr {
strong_compact_ptr(strong_compact_ptr&& rhs) = delete;
~strong_compact_ptr() noexcept(std::is_nothrow_destructible_v<T>) {
if (ptr_->strong_count.fetch_sub(1, std::memory_order::acq_rel) == 1) {
std::destroy_at(operator->());
operator->()->~T();
if (ptr_->weak_count.fetch_sub(1u, std::memory_order::release) == 1) {
deallocate(ptr_->alloc, ptr_);
}
Expand Down
75 changes: 75 additions & 0 deletions tests/proxy_lifetime_tests.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,14 @@ struct TestTrivialFacade
::support_destruction<pro::constraint_level::trivial> //
::build {};

struct TestThrowingDestructionFacade
: pro::facade_builder //
::add_convention<utils::spec::FreeToString, std::string()> //
::support_copy<pro::constraint_level::nontrivial> //
::support_relocation<pro::constraint_level::nontrivial> //
::support_destruction<pro::constraint_level::nontrivial> //
::build {};

struct TestRttiFacade : pro::facade_builder //
::add_direct_reflection<utils::RttiReflector> //
::add_facade_with_substitution<TestFacade> //
Expand Down Expand Up @@ -274,6 +282,21 @@ TEST(ProxyLifetimeTests, TestMoveConstrction_FromNull) {
ASSERT_FALSE(p2.has_value());
}

TEST(ProxyLifetimeTests, TestDestruction_Exception) {
utils::LifetimeTracker tracker;
std::vector<utils::LifetimeOperation> expected_ops;
auto destroy = [&] {
pro::proxy<detail::TestThrowingDestructionFacade> p{
std::in_place_type<utils::LifetimeTracker::ThrowingDestructionSession>,
&tracker};
};
ASSERT_THROW(destroy(), utils::DestructionFailure);
expected_ops.emplace_back(1,
utils::LifetimeOperationType::kValueConstruction);
expected_ops.emplace_back(1, utils::LifetimeOperationType::kDestruction);
ASSERT_TRUE(tracker.GetOperations() == expected_ops);
}

TEST(ProxyLifetimeTests, TestNullAssignment_FromNullptr_ToValue) {
utils::LifetimeTracker tracker;
std::vector<utils::LifetimeOperation> expected_ops;
Expand Down Expand Up @@ -358,6 +381,30 @@ TEST(ProxyLifetimeTests, TestPolyAssignment_ToValue_Exception) {
ASSERT_TRUE(tracker.GetOperations() == expected_ops);
}

TEST(ProxyLifetimeTests, TestPolyAssignment_ToValue_DestructionException) {
utils::LifetimeTracker tracker;
std::vector<utils::LifetimeOperation> expected_ops;
{
pro::proxy<detail::TestThrowingDestructionFacade> p{
std::in_place_type<utils::LifetimeTracker::ThrowingDestructionSession>,
&tracker};
expected_ops.emplace_back(1,
utils::LifetimeOperationType::kValueConstruction);
utils::LifetimeTracker::Session session{&tracker};
expected_ops.emplace_back(2,
utils::LifetimeOperationType::kValueConstruction);
ASSERT_THROW(p = session, utils::DestructionFailure);
ASSERT_FALSE(p.has_value());
expected_ops.emplace_back(3,
utils::LifetimeOperationType::kCopyConstruction);
expected_ops.emplace_back(1, utils::LifetimeOperationType::kDestruction);
expected_ops.emplace_back(3, utils::LifetimeOperationType::kDestruction);
ASSERT_TRUE(tracker.GetOperations() == expected_ops);
}
expected_ops.emplace_back(2, utils::LifetimeOperationType::kDestruction);
ASSERT_TRUE(tracker.GetOperations() == expected_ops);
}

TEST(ProxyLifetimeTests, TestPolyAssignment_FromValue_ToNull) {
utils::LifetimeTracker tracker;
std::vector<utils::LifetimeOperation> expected_ops;
Expand Down Expand Up @@ -630,6 +677,34 @@ TEST(ProxyLifetimeTests, TestCopyAssignment_FromValue_ToValue_Exception) {
ASSERT_TRUE(tracker.GetOperations() == expected_ops);
}

TEST(ProxyLifetimeTests,
TestCopyAssignment_FromValue_ToValue_DestructionException) {
utils::LifetimeTracker tracker;
std::vector<utils::LifetimeOperation> expected_ops;
{
pro::proxy<detail::TestThrowingDestructionFacade> p1{
std::in_place_type<utils::LifetimeTracker::ThrowingDestructionSession>,
&tracker};
expected_ops.emplace_back(1,
utils::LifetimeOperationType::kValueConstruction);
pro::proxy<detail::TestThrowingDestructionFacade> p2{
std::in_place_type<utils::LifetimeTracker::Session>, &tracker};
expected_ops.emplace_back(2,
utils::LifetimeOperationType::kValueConstruction);
ASSERT_THROW(p1 = p2, utils::DestructionFailure);
ASSERT_FALSE(p1.has_value());
ASSERT_TRUE(p2.has_value());
ASSERT_EQ(ToString(*p2), "Session 2");
expected_ops.emplace_back(3,
utils::LifetimeOperationType::kCopyConstruction);
expected_ops.emplace_back(1, utils::LifetimeOperationType::kDestruction);
expected_ops.emplace_back(3, utils::LifetimeOperationType::kDestruction);
ASSERT_TRUE(tracker.GetOperations() == expected_ops);
}
expected_ops.emplace_back(2, utils::LifetimeOperationType::kDestruction);
ASSERT_TRUE(tracker.GetOperations() == expected_ops);
}

TEST(ProxyLifetimeTests, TestCopyAssignment_FromValue_ToSelf) {
utils::LifetimeTracker tracker;
std::vector<utils::LifetimeOperation> expected_ops;
Expand Down
13 changes: 13 additions & 0 deletions tests/utils.h
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@
#ifndef _MSFT_PROXY_TEST_UTILS_
#define _MSFT_PROXY_TEST_UTILS_

#include <exception>
#include <proxy/proxy.h>
#include <string>
#include <vector>
Expand Down Expand Up @@ -38,6 +39,8 @@ struct ConstructionFailure : std::exception {
LifetimeOperationType type_;
};

struct DestructionFailure : std::exception {};

class LifetimeTracker {
public:
LifetimeTracker() = default;
Expand Down Expand Up @@ -74,6 +77,16 @@ class LifetimeTracker {
LifetimeTracker* const host_;
};

class ThrowingDestructionSession : public Session {
public:
using Session::Session;
~ThrowingDestructionSession() noexcept(false) {
if (std::uncaught_exceptions() == 0) {
throw DestructionFailure{};
}
}
};

const std::vector<LifetimeOperation>& GetOperations() const { return ops_; }
void ThrowOnNextConstruction() { throw_on_next_construction_ = true; }

Expand Down
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